Wanted to humbly ask some guidance. Homeowner before us added an ugly concrete shower base, that was too ugly to tile, etc (pic below). So I took it out hoping to rebuild the shower base, frame and waterproof the walls and then tile. Well after taking out the curb, and base much to my dismay I found that the shower drain was just sitting in a massive hole inside the drain pipe it was tapped into - no p trap/no nothing (only attached via the poured concrete). As such I have attached pictures of what the hole in the pipe looks like and prior to moving forward I wanted to obtain some guidance. Can the existing pipe be cut and attached rubber boots/couplings to pvc and then tie in a new drain and trap to the pvc? Or is there another way I should go about this? All help is needed. I am in Indiana - any coding issues I need to be made aware of as well would be helpful. Thank you in advance.